End of train devices, referred to generally as EOT's, EOTD's, EOT systems, and by similar nomenclature, are in widespread use in the modern rail environment. Functions additionally performed by personnel in a caboose or the like are automated to varying degrees, including producing a visible blinker signal at the end of the train, location tracking, and, perhaps most importantly, informing the front of train systems and personnel, as to brake system status at the last railcar in a train.
Most modern railcars employ pneumatic brakes coupled together in a series arrangement car-to-car, and supplied with pressurized actuating air from a compressor onboard the locomotive or otherwise near the front of the train. Among other things, ensuring that sufficient pressure is available for brake actuation at the last railcar can enable slowing or stopping the train in a desired manner, generally uniform application of braking force throughout the train, and avoiding the use of emergency brakes or other problems.
The hardware and functionality of end of train devices is commonly situated in a portable housing that can be attached to suitable mounts at the back end of the train. While certain charging or power generating strategies have been proposed, most end of train devices rely upon batteries for powering the various electrical components. Traditional and conventional batteries in such applications such as lead acid batteries tend to be heavy, weighing dozens of pounds, sometimes requiring the engineer or other personnel to lift and carry the device to and from a station for charging or swapping with another end of train device, or for various other purposes. U.S. Pat. No. 5,267,471 proposes a power supply for an EOT unit where an electrical generator driven by air from the train airbrake pipe provides power to the EOT unit. While the '473 patent proposes strategies that may have certain advantages, there is ample room for continued and alternative developments in this field.